Sound transmitter



10.-.'192-8. l v ;w. l.. WALKER Y souNngTRANsMI-T'TER origina; Filed .M'rfn 18j; 192g Patentes Jui'y' 1.0,' 192s.

UNITED STATESV PATENT orrics. 1

WILLIAM L. WALKER, oF NEW-YORK, N. Y.

SOUND' 'TRANSMITTER'.

Application iled March 18, 1922Seria1 No.544,962. Renewed October 21, 1927.

My invention relates particularly to means for generating and transmitting sound v1- brations or oscillations in an elastic medium,

and particularly in water; Theinvention is especially applicable to transmission'of subiriarine sound. signals from one vessel to another or'from lan-d'stations to vessels in.

the vicinity of said stations.

The object of my invention is the production of strong sustained oscillations or vibrations of water or other medium so that the same may be transmitted long distances and with the least possible consumption of power. In other words, I am enabled to 'obtain high efficiency in sound generation and transmission through the use ot simplified and practically unitary parts without making use of joints or pivots which con# sume energy and; which occupy considerable space. .To attain high efiiciency it is necessary that the apparatus be designed so that it shall make use of the best known acoustic principles in order to convert the energy which generates tlie'sound from electrical to mechanicalor acoustic form.

It is known that nearly all bodies of elastic material have a certain natural period of vibration similar to the natural oscillatingr period 'of an electrical circuit, and in order' to have the sound transmitting apparatus efhcient, the principle of resonance must bew taken into account and the apparatus so designed that the natural period of vibration will be as nearly that desired as possible, since it requires much greater energy to energize a vibrating body at some otherperiod than its own natural period of vibration onI account of the damping effect.

Furthermore, owing to inertia and high damping effect of large bodies of fluid, such as water, the vibrations impressed upon such bodies of fluid must be of low amplitude, but

. at the same time be produced Aby strong forces. On the other hand, the vibrations produced by the alternating field of an electromagnet must be of considerable ampli` tude and of comparatively'reduced force. It therefore becomes necessary to transform or convert the comparatively large -amphf tudes of vibrating armatures of an electromagnet into vibrations or oscillationsl of comparatively small amplitude aiid, la.rge r force 'at the point` wherethe same-are inrpressed upon the transmitting fluid.

These principles have been embodied in the apparatus which is described below taken in connection with the accompanying drawings which forma 'part of the specification.

In said drawing Fig. 1 is a longitudinal sectional View of o'ne form of my. improved apparatus taken substantially on the linel ln-l of .F ig. 2. Fig. 2 is a. transverse sectional vieiv taken substantially on the line or other structure from which it is 'desiredfto' transmit sound waves. The numerall indi;v

Cates a. iianged collar secured to the sideof I the ship by means of bolts 3, and having, a

cylindricalpart 30 which lies substantiallyflush with the outer surface of the side 6 and is provided with an inwardly extending rib or fiange29 for engaging the outer end of the amplifyingl portion 4 of the apparatus secured to the .flanged collar 1 by means lof This amplifying-or bell shaped portion 4 is bolts 2 passing through outwardly extending flange 4. phra m which closes the outer end of the anipliier 4 and lies flush with the sides 6 'of the vessel or other structure, in order to prevent eddy currents and undesirable sounds produced thereby. LThe electromagnetic sound generating ldevice is attached to the inner The letter D indicates a diaend of the amplifier 4 as indicated atl 18 and ,Q

consists essentially of the ffollowing parts: The numeral 7 indicates ajtube of resilient material such as bronze, or steel coated or plated to prevent corrosiveA action of the water. .This'tube is flattened as indicated in Fig. 2 in order'that the attened sides 9 may vibrate toward and away from eachV other. One end of this tube 7`is fixed to the amplifier as at 18 and the other endengages the plug .orl block 8 which is bolted to a frame comprising the brackets or supports 25. The inner end of the amplifier 4 1s also provided with .l similar brackets 13 between .which and. the brackets 25 the. laminated c'ores'23 are heldliy` The pairs of brackets13 Vand 25 'areeach connected together transversely by vmeans of semicircular connecting"l i vbraces 26 and26. The platesof the cores 23 of the electromagnets are clamped between wings 14an'd 20 by means of suitable rivets.

or bolts, as indicated. The cores 23. of the electroma'gnets are preferably' given the shape indicated in Fig. 1 and are provided with widened pole pieces 17 and 21, as indi-` cated. The energizing coils 24 are mounted on the connecting horizontal portions of these cores and are energized in any suitable Way, sufch as by an alternating current dynamo having the desired period of vibration or oscillation required to be transmitted to the water. The armatures 16 are rigidly mounted on the fiat sides 9 of the tube 7 and are separated from the pole pieces 17 and 21 by small air gaps 19, but are sutiiciently close to allow the said armatures to come into contact with said pole pieces. The interiors of the tube 7 and the' amplifier are preferably filled with fiuid such as water and are preferably hermetically closed; Howeven a pipe 27 having a valve 28 therein is provided to allow communication between the outside Water and the inside of the amplifier so that vWard and then allow them to move inward owing to the action of the elasticity of the tube 7. This will alternately increase and reduce the volumeof liquid in the said tube 7 and cause a longitudinal vibration of said liquid at the right hand end 18 of said tube, as shown in Fig. 1. This will set the liquid Within the amplifier 4 into vibration at a corresponding period and will consequently ,vibrate the diaphragm D. However, these respective actions will operate in a way similar tothe action of a force pump in an hydraulic press; that is, the displacement of the liquid at the right hand end of the tube 7 will be spread out over the entire surface of the diaphragm D so that the total pressure on said vdiaphragm during each quarter period of vibration will be in the proportion of the areal of said diaphragm to the cross section of said tube, while the amplitude of the vibrations of said diaphragm will be decreased correspondingly. Thus the conversion of the energy of thel electromagnets is accomplished without any movable mechanical parts .and practically all of the energy used in said magnets is transmittedto the water on the outside of said diaphragm.

The pipe 27 and the valves 28 and 29 may be omitted and small holes placed in the diaphragm for the ingress of water and the egress of air, as described in connection with nordsee the modification of the device, as follows:

The modification shown in Figs. 3 and 4 is similar to that of Figs. 1 and 2, and differs therefrom in that the armatures of the elec tromagnets are not connected directly with the vibrating tube.

In Figs. 3 and et the tube 7 is substantially inclosed between two curved plates 31 of a magnetic material similar in cross-section to the shape of the tube. The plates 81 are se cured at their ends to the tube 7 as at 32, or in ahy other suitable manner, so that when vibrated by the action of the pole pieces 17 and 21 under the influence of the magnetic field of the coils 24, they will impinge upon the tube 7 and thereby strike it with a succession of sharp blows. This will displace the fluid within the tube 7 in a manner similar to that above described.

.The numeral B3-.indicates smallholes adjacent the margin ofthe diaphragmfor the admission of water and the egress of air, as

above referred to. f

, In the above arrangements the parts may be so designed that the elasticity of the tube, the volume of the liquid therein and in the amplifier 4, and the elasticity of the diaphragm D may be sc proportioned that the natural period of 'vibration will correspond very closely to the period of the impressed magnetic field reduced by the coils l24. Thus there would be practically no damping effect which would otherwise exist owing to a lack of resonance, and there are no pivoted parts which would 'produce friction and so tend to consume energy.

`Having thus described this'form of my invention, I do not wish to be understood as being limited to the details of form and arrangement of parts set forth7 for various changes may be made without, 'departing from the spirit and. scope of my invention.

What T claim and desire to protect by Letters Patent is:

1. A submarine signaling transmitter comprising ari enclosing easing, enlarved at one end portion, a vtransverse resilient diaphragm closing said enlarged end, a resil-A ient tubular portion communicating with said enlarged end portion, a substantially non-compressible liquid within said casing and means for vibrating said tubular portion whereby vibrations are impressed upon said diaphragm through said liquid.

2. A submarine signaling transmitter comprising an enclosing casing, enlargedv at one end portion,v a transverse'resilient.diaphragm closing said enlarged end, a tubular portion having longitudinal resilient walls and communicating with said enlarged end portion,' a substantially non-compres` sible liquid within said casing, the natural vibration period of the resilient portions and said fluid being substantially the same, and means 'for vibrating said longitudinal on i.

walls whereby vibrations are impressed upl on said diaphragm.

3. A submarinel signaling transmitter comprising an enclosing casing, enlarged at 4one end portion, a' transverse resilient diaphragm closing said enlarged end, a tubular' portion having resilient, flattened side walls an'd communicating with said enlarged end portion, a substantially non-compressible liquid contained insaid casing, and

- means for vibrating said iattened side walls,

portion, a substantially non-compressible.

liquid Withinsaid casing, and electro-mag# netic means for vibrating said longitudinal walls. A

5. A submarine signaling transmitter comprising a resilient elongated `hollow member having attened parallel sidewalls.,

resilient armatures operatively vconnected with and adapted to strike upon lsaid walls for vibrating the sametoward and from each other, and electro-magnets for operating said armatures.

6. A submarine comprising a resilient elongated hollow member having flattened side walls and open at one end, resilient armatures supportedat y their' ends and adapted to strike vupon said walls for vibrating thesame, electro magnets for operating said armatures, and a non-resilient casing connected with said hollow memberat its open end and having at its opposite end a resilient wall, the area of which is greaterlthan the area. of said hollow member, said casing and member being filled with a substantially non-compressible liqpid." v

. A submarine signaling transmitter comprising a resilient elongated hollow signaling transmitter member having flattened side walls and` open at one end, resilient armatures connected at their ends with and adapted to strike upon said walls for vibrating the same, electro-magnets for operating said armatures, a non-resilient casing connected with said hollow member at its open end and a resilient diaphragm carried at the outer end of said. easing. i,

8. A submarine .signaling transmitter comprising a resilient elongated hollow member having flattened side walls and open at one end, resilient armatures in the form of strips of magnetic material sup ported at their ends :and attached thereat to the opposite ends of saidv side walls, the central portions thereof being adapted to strike upon said side' walls forvibrating the same, elctro magnets for operatingsaid armatures, a non-resilient .casing connected with -said hollow member at its open end and a resilient diaphragmcarried at the outer end of said casing.

9. A submarine signaling transmitter comprising .a resilient elongated hollow member having flattened' side walls and open at one end, resilient armatures comprising strips of magnetic material attached to saidv side walls at their ends, electro mag-- nets having opposite poles located adjacent each of said strips, a non-resilient casing connected with said hollow member at its open end and a resilient. diaphragm carried Vat the'outer end of said casing.

10. submarine signaling transmitter comprlsmg fa resilient elongated hollow member having flattened side walls and 'open at one end, resilient armatures come prlsm strips of `magnetic material attachedto sai side walls at their ends, electromagnets of horse-shoe form having energizing coils located on the yoke portion of 'the same, a non-resilient casing connected with said hollow member at its open end and a resilient diaphragm carried' at the outer end of said casing.

WILLIAM-L. WALKER.v 

